DescriptionAdults 60-80 mm. Tibiotarsal articulation reaches at most the nostril. Hand without webbing, foot completely webbed. Terminal discs of fingers and toes strongly enlarged. Tympanum rather indistinct and small (1/4 of eye diameter). Dorsal skin smooth. Colour olive greenish, especially in subadults, to brown, with lighter or darker indistinct markings. Ventrally white, often with dark spots or marblings on throat and chest. Males without femoral glands.

Similar species: This large species can easily be mistaken with Mantidactylus grandidieri and M. guttulatus which, however, have less expanded discs on fingers and toes. Smaller specimens can also be mistaken with Spinomantis microtis which occurs in south-eastern Madagascar as well but appears to be confined to higher elevations. Juveniles may also be confused with Mantidactylus lugubris and related species which can occur syntopically.

Ambana, Andohahela, Bekazaha, Chaines Anosyennes, Isaka-Ivondro, Manantantely, Nahampoana, Soavala. It occurs between 50-1,000m asl in degraded and pristine forest and open area next to relict forest (Nussbaum et al. 2008).

Life History, Abundance, Activity, and Special BehaviorsHabits: Often found on large stones in torrents. Mainly active at night, but sometimes found jumping on the stones in the afternoon, together with M. lugubris.
Call: Unknown. The frogs live in very noisy torrents, and considering the reduced tympanum, M. microtympanum may be a non-calling species.
Eggs and tadpoles: Unknown. Juveniles, already with a visible, very small tympanum, and a SVL of 16 mm, were found in January at Nahampoana.

Trends and ThreatsEndangered because its area of occupancy is less than 500km2, all individuals are in fewer than five locations, and there is likely to be continuing decline in the extent and quality of its forest habitat in southeastern Madagascar. It occurs in the Andohahela and Midongy-du-Sud National Parks (Nussbaum et al. 2008).

Written by Miguel Vences and Frank Glaw (m.vences AT tu-bs.de), Assistant Professor and Curator of Vertebrates at the Institute for Biodiversity and Ecosystem Dynamics in the Zoological Museum at the University of Amsterdam.First submitted 2000-12-13Edited by Henry Zhu (2010-07-19)